1. Field of the Invention
The present invention relates to seed meters for metering seeds therefrom during a planting operation, and more particularly to seed meters of the type in which a mass of seeds is stored within a housing and adjacent a rotating seed disk for pickup and dispensing of individual seeds from the mass by the seed disk.
2. History of the Prior Art
It is known in the agricultural equipment field to provide seed meters for metering or dispensing individual seeds from a seed mass at a controlled rate during a planting operation. Many seed meters are of the air type in which a positive air flow or a vacuum is used to assist in holding the individual seeds in place on a rotatable or otherwise movable member for eventual discharge from the meter to a furrow in the ground below.
An example of a vacuum seed meter is provided by a co-pending application of Lundie et al, Ser. No. 546,834, filed Oct. 31, 1983 and commonly assigned with the present application. The vacuum seed meter described in the Lundie et al application has a seed disk rotatably mounted within a generally cylindrical housing so as to define a seed chamber on one side of the disk within the housing and a vacuum chamber on the other side of the disk and within the housing. A vacuum source coupled to the vacuum chamber creates a vacuum therein which communicates with a circumferential array of apertures in the seed disk extending through the thickness thereof to the bottoms of seed cells on the opposite side of the seed disk. As the seed disk rotates through a mass of seeds within the seed chamber, the seed cells in the disk agitate, accelerate and then capture therein individual seeds. As the cells rise above the seed mass with rotation of the seed disk, the vacuum within the vacuum chamber on the opposite side of the disk communicates through the apertures in the disk to hold the individual seeds in place within the seed cells. As the seed disk continues to rotate, the individual seed cells eventually reach a seed discharge area where the effects of the vacuum are cut off from the apertures, allowing the seeds to fall out of the seed cells with the effects of gravity. As the individual seeds fall out of the seed cells within the seed discharge area, the seeds fall down a chute at the bottom of the seed meter to the ground below.
In the vacuum seed meter described in the co-pending application of Lundie et al, as in the case of most seed meters, continued use of the meter causes dirt and other debris to accumulate within the meter. Part of such debris is comprised of broken seeds and seed chips or particles. Such debris interferes with the operation of the seed meter and therefore is desirably eliminated. While some of the debris is eliminated by being drawn through the seed cells and connecting apertures by the vacuum, debris still collects within the seed meter where it can build up and interfere with proper operation if not removed.
Prior seed meters have provided various arrangements for eliminating debris therefrom. For example, in U.S. Pat. No. 3,888,387 of Deckler a rotating member within a seed meter which picks up and carries seeds within pockets therein adjacent the outer edge thereof has a series of passageways at the outer edge to establish a pressure differential with the pockets. The passageways are also configured to have the effect of wiping an adjacent surface to prevent dust buildup and to purge chips or broken seeds from the pockets. In other examples of prior art seed meters, debris is expelled through a gap between a rotating seed member and a housing. Unfortunately, design of such gaps usually makes them rather ineffective. Moreover, the gap is usually fixed in size so as to provide the necessary seal for seeds of larger size but not for seeds of smaller size. Still other areas of the prior art as exemplified by U.S. Pat. No. 3,664,675 of Malmstrom teach that a rib member rotatable relative to and in contact with another member can provide a radially directed pumping effect. However, nothing in the art provides a solution to the problem of providing effective and reliable elimination of debris from seed meters of the type described in the previously referred to co-pending application of Lundie et al.
Accordingly, it would be desirable to provide a seed meter having an improved arrangement for eliminating debris therefrom. It would furthermore be desirable to provide a seed meter having an effective arrangement for eliminating debris therefrom which is useful with seeds of different sizes.